wxgeek's weather-Warm/Dry then Snow/Cold Nxt Wk-Update 10/25

Update Fri Oct 25

Weak upper level trough moving across southwest CO today bringing some showers and thunderstorms to the southwest portion of the state, with some showers spreading into the central mountains and southern foothills. Snow around 10,000 to 11,000 ft. This system will move east along the CO/NM border tonight leaving mostly sunny skies and mild temps for the weekend across the state.

The next system remains rather elusive to numerical models at this point, as each model has it's own unique solution for the track of this system. Thus, not much confidence in the forecast for next week at this point. All models dig an upper level trough from western Canada down into either the Great Basin or CA by Monday, with the GFS having a closed low over southwest ID, and the ECMWF having the closed low over northeast CA, while the NAM has the low over south central ID. Models then diverge on the track further. ECMWF keeps the closed low back over central CA on Tuesday, while the GFS brings it east into northern UT Tuesday. By Wednesday, ECMWF has the upper low over central UT while the GFS has moved it to an open trough over CO. Each model has a corresponding different pattern at the surface which influences precipitation. In general, the ECMWF keeps most precip west of CO and does not bring a strong cold front into northeast CO while the GFS brings a better cold front into northeast CO Monday night and brings some decent precip to eastern CO Tuesday night. My hunch is that the eventual solution will be somewhere between where the ECMWF and GFS are now, which would mean a cold front may wait until Tuesday to push into northeast CO, and precip could wait until Tuesday night into Wednesday morning. Will have to wait see how models evolve this and hopefully come to some kind of consensus before any snowfall estimates can be made. Definitely will be a change in weather next week, just not sure the exact timing and how much snow at this point.

The remainder of next week looks dry currently into next weekend.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

---

Update Wed Oct 23

More beautiful weather across CO and most of the western U.S. while upper ridge is in place, while cold weather gripping the eastern U.S. as large upper trough persists. Dry and mild weather expected to continue across CO through this coming weekend, with only a slight chance for showers across the southwest portion of the state on Friday.

Models are going through their usual iterations for the change in weather early next week. Overall, an upper trough is forecast to move from western Canada into the western U.S. early next week. The exact track, intensity and timing are still up for debate as GFS and ECMWF have had several different solution the past 48 hours. Currently, the GFS is farther west and slower, while the ECMWF is farther east and faster. For CO, the GFS solution would provide warmer temps and less precip keeping the bulk farther west, while the ECMWF would provide colder temps and more precip. Either way, the onset of colder temps and precip look to be delayed until at least Monday night, perhaps as late as Tuesday, and could persist into Wednesday night. I expect models to continue their iterations and disagreements into the weekend, until this system moves into western Canada, so not much point trying to guess too far ahead on this one. Bottom line is colder temps and chances for snow will exist across CO from Monday night into Wednesday night next week. System has the potential to develop into a decent Fall snowstorm, but it also has the potential to fizzle out and not go much at all over CO, so will have to wait and see how model evolve this one.

Currently in Memphis on a biz trip, and the Westin hotel downtown allows guests to check out and play a wide range of Gibson guitars from the Gibson guitar museum across the street, quite fun to play some very nice guitars I otherwise could not afford to buy.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

---

Update Tue Oct 22

Beautiful Indian Summer weather across the state today with temps 5-10 degrees above seasonal norms. Nice weather will continue into this coming weekend, with temps back near seasonal norms Thu and Fri, then 5-10 degrees above this weekend again. This weather is associated with a blocking upper level pattern over the eastern Pacific and western U.S. Some showers may be possible across the southwest and south central mountains Friday with snow level 10,000 to 11,000 ft.

A big change will occur early next week as the upper ridge moves west into the eastern Pacific and allows an upper level trough to move south from western Canada into the northern and central Rockies. GFS and ECMWF are in decent agreement on the pattern, but have slight timing differences with the ECMWF being slower and deeper, which is pretty common. In general, as upper trough moves south, a cold front will move south across CO sometime on Monday, depending on timing could be late morning or evening. Upslope flow and snow will develop behind the cold front and spread south over CO, mostly along and east of the Divide. Snow level will initially begin around 7000-8000 ft but quickly lower to plains level as very cold air moves across the state. Snow looks likely to persist into Tuesday during the day and diminish by Tuesday evening/night. If models are correct, this system could dump several inches of snow across the mountains, foothills and plains. Still a ways out, so not worth trying to pin down timing and snow amounts just yet, but be prepared for a big change in the weather early next week. I will keep an eye on future models runs and begin to pin down timing and amounts as we get closer to the weekend.

After this next system, models re-build the upper ridge over the western U.S. which looks to keep CO dry and mild for the remainder of next week into next weekend.

Hurricane Raymond is appx 90 miles WSW of Acapulco and has decreased in intensity to a Category 1 hurricane with sustained winds of 75 mph. Raymond continues to spin just off the coast creating heavy rain, surf and winds along the Mexico coast between Acapulco and Manzanillo. Raymond will begin to slowly move west away from the coast on Wednesday and continue out farther to sea into the week.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

---

After a brief dusting to an inch of snow Sunday, sunny and warm weather is expected for the remainder of the week and into the weekend. Temps expected to be slightly above seasonal norms Tuesday and Wednesday, then near seasonal norms the remainder of the week into the weekend. Upper level ridge will build into the Inter-Mountain West this week keeping temps mild and moisture well to our north through the weekend.

Latest medium range models now have the upper ridge retrograding westward back into the eastern Pacific early next week, which allows another cold system from western Canada to plunge south into the northern and central Rockies. If this pattern unfolds as models suggest, snow would move into the northern Rockies on Sunday, and spread into CO on Monday into Tuesday. Another chance for precip would exist late next week as an upper level low off Baja ejects northeast across CO.

Hurricane Raymond is currently just off the west coast of Mexico between Acapulco and Mazatlan and is expected to remain nearly stationary then move slowly west later in the week. Very heavy rain with flooding and mudslides will likely occur in this region.

Latest seasonal forecast from the Climate Prediction Center for the November-January period just issued. For CO, the forecast calls for above average temps for the preiod, with near normal precipitation.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

Bump for 10/22 Update

Bump for 10/25 Update